Capacity control valve and capacity control valve control method

ABSTRACT

A capacity control valve includes: a valve body having first communication passages, second communication passages, third communication passages, and a main valve seat; a valve element having an intermediate communication passage, a main valve portion and an auxiliary valve portion; a pressure-sensitive element disposed in the valve body; a solenoid that drives a rod; a first biasing member that biases in a valve closing direction of the main valve portion; and a second biasing member that biases in a valve opening direction of the main valve portion, wherein the rod moves relative to the valve element to press the pressure-sensitive element. The capacity control valve can efficiently discharge a liquid refrigerant and can decrease a driving force of a compressor during a liquid refrigerant discharge operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 16/763,800, filed May 13, 2020, which in turn is a U.S.National Phase under 35 U.S.C. § 371 of International ApplicationPCT/JP2018/041768, filed Nov. 12, 2018, which claims priority toJapanese Patent Application No. 2017-220521, filed Nov. 15, 2017. Thecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a capacity control valve suitable forcontrolling a flow rate or a pressure of a variable capacity compressorand a method of controlling the capacity control valve.

BACKGROUND ART

As a variable capacity compressor, for example, a swash plate typevariable capacity compressor suitable for an air-conditioning system ofan automobile or the like includes a rotating shaft rotationally drivenby a rotational force of an engine, a swash plate coupled to therotating shaft such that the plate's angle of inclination can be varied,a piston for compression coupled to the swash plate, and the like. Byvarying the angle of inclination of the swash plate to vary the strokeof the piston, the compressor controls the discharge rate of arefrigerant.

The angle of inclination of the swash plate can be continuously variedby utilizing a suction pressure in a suction chamber for drawing in therefrigerant, a discharge pressure in a discharge chamber for dischargingthe refrigerant pressurized by the piston, and a control chamberpressure in a control chamber (a crank chamber) in which the swash plateis housed, while appropriately controlling the pressure in the controlchamber using a capacity control valve that is driven to be opened andclosed by an electromagnetic force, and thereby regulating the balanceof pressures acting on opposite faces of the piston.

FIG. 7 shows an example of such a capacity control valve. A capacitycontrol valve 160 includes: a valve unit 170 having a second valve chest182 communicating with a discharge chamber of a compressor through asecond communication passage 173, a first valve chest 183 communicatingwith a suction chamber through a first communication passage 171, and athird valve chest 184 communicating with a control chamber through athird communication passage 174; a pressure-sensitive element 178 thatis arranged in the third valve chest to extend and contract with anambient pressure and has a valve seat element 180 provided at free endin a direction of extension and contracting; a valve element 181 havinga second valve portion 176 that opens and closes a valve hole 177communicating the second valve chest 182 and the third valve chest 184,a first valve portion 175 that opens and closes the first communicationpassage 171 and a flow channel 172, and a third valve portion 179 thatopens and closes the third valve chest 184 and the flow channel 172 bybeing engaged with and disengaged from the valve seat element 180 in thethird valve chest 184; a solenoid unit 190 that exerts anelectromagnetic driving force on the valve element 181; and others.

Furthermore, even though a clutch mechanism is not provided in thevariable capacity compressor, in a case where it becomes necessary tovary the control chamber pressure, the capacity control valve 160 cancontrol a pressure Pc in the control chamber (a control chamberpressure) and a suction pressure Ps (a suction pressure) by making thedischarge chamber and the control chamber communicate with each other(hereinafter referred to as a “conventional art”. See, for example,Patent Document 1).

CITATION LIST Patent Document

-   Patent Document 1: JP 5167121 B1

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the conventional art, in a case where the swash plate type variablecapacity compressor is stopped for a long period of time, a liquidrefrigerant (a refrigerant that has been liquefied by cooling while thecompressor is inoperative) accumulates in the control chamber (the crankchamber). If the compressor is activated in this state, the presetdischarge rate cannot be ensured. Therefore, in order for the desiredcapacity control to be performed immediately after the activation, it isnecessary for the liquid refrigerant in the control chamber (the crankchamber) to be discharged as quickly as possible.

Therefore, as shown in FIG. 8 , the conventional capacity control valve160 is provided with a liquid refrigerant discharge function todischarge the liquid refrigerant in the control chamber (the crankchamber) as quickly as possible at the time of activation. That is, in acase where the variable capacity compressor has been stopped, leftinoperative for a long period of time, and is then activated, thehigh-pressure liquid refrigerant accumulated in the control chamber (thecrank chamber) flows through the third communication passage 174 intothe third valve chest 184. Then, the pressure-sensitive element (thebellows) 178 contracts, and a gap opens between the third valve portion179 and the valve seat element 180. From the third valve chest 184through an auxiliary communication passage 185, a communication passage186, and the flow channel 172, the liquid refrigerant is discharged fromthe control chamber (the crank chamber) through the suction chamber tothe discharge chamber to be rapidly vaporized, enabling the compressorto be brought into a cooling operation in a short time.

However, in the above conventional art, in the early stage of the liquidrefrigerant discharging process, the pressure in the control chamber ishigh, so that the opening of the third valve portion 179 is large andthe liquid refrigerant can be discharged efficiently. Unfortunately, asthe discharge of the liquid refrigerant progresses and the pressure inthe control chamber decreases, the opening of the third valve bodybecomes smaller, requiring time to discharge the liquid refrigerant.

Conventionally, during the liquid refrigerant discharge operation,attention has been focused only on how to complete the discharge of theliquid refrigerant in a short time, and thus the control for reducingthe engine load during the liquid refrigerant discharge operation hasnot been performed. However, if the liquid refrigerant dischargeoperation is performed when the engine load is high, the engine loadfurther increases, resulting in a decrease in energy efficiency of theentire automobile.

The present invention has been made in order to solve the problems ofthe conventional art, and its object is to provide a capacity controlvalve that controls a flow rate or a pressure of a variable capacitycompressor according to a valve opening of a valve unit, in which aliquid refrigerant can be efficiently discharged regardless of apressure in a suction chamber to shift the compressor to a coolingoperation in a short time and a driving force of the compressor can bedecreased during a liquid refrigerant discharge operation, and a methodof controlling the capacity control valve.

Means for Solving Problem

In order to solve the above problems, a capacity control valve accordingto a first aspect of the present invention that controls a flow rate ora pressure of a variable capacity compressor according to a valveopening of a valve unit, is characterized by including:

a valve body including first communication passages that pass fluidunder a first pressure, second communication passages that are arrangedadjacent to the first communication passages and pass fluid under asecond pressure, third communication passages that pass fluid under athird pressure, and a main valve seat that is disposed in a valve holecommunicating the second communication passages and the thirdcommunication passages;

a pressure-sensitive element that is arranged in the valve body on theside of the third communication passages and extends and contracts inresponse to an ambient pressure;

a valve element including an intermediate communication passage thatcommunicates the first communication passages and the thirdcommunication passages, a main valve portion that is separated from andcomes into contact with the main valve seat to open and close the valvehole, and an auxiliary valve portion that is separated from and comesinto contact with the pressure-sensitive element to open and close theintermediate communication passage;

a solenoid that drives a rod;

a first biasing member that biases in a valve closing direction of themain valve portion; and

a second biasing member that biases in the valve opening direction ofthe main valve portion, wherein

the rod moves relative to the valve element to press thepressure-sensitive element.

According to this aspect, the rod can be moved relative to the valveelement to press the pressure-sensitive element, allowing the auxiliaryvalve portion to be forcibly opened, so that an opening of the auxiliaryvalve portion can be kept in the fully open state from the start of theliquid refrigerant discharge to the completion of the liquid refrigerantdischarge, and the liquid refrigerant can be efficiently discharged.

The capacity control valve according to a second aspect of the presentinvention is characterized in that a biasing force of the second biasingmember is larger than a biasing force of the first biasing member.

According to this aspect, even when the biasing force of thepressure-sensitive element does not act on the valve element, the mainvalve portion can be opened by the biasing force of the second biasingmember, and the main valve portion and the auxiliary valve portion canbe opened and closed in any combination.

The capacity control valve according to a third aspect of the presentinvention is characterized in that the first biasing member is disposedbetween the solenoid and the valve element.

According to this aspect, since the first biasing member is disposedbetween the solenoid and the valve element, it is possible to ensurethat the valve element is biased in the valve closing direction of themain valve portion.

The capacity control valve according to a fourth aspect of the presentinvention is characterized in that the second biasing member is disposedbetween the pressure-sensitive element and the rod.

According to this aspect, since the second biasing member is disposedbetween the pressure-sensitive element and the rod, it is possible toensure that the valve element is biased in the valve opening directionof the main valve portion.

The capacity control valve according to a fifth aspect of the presentinvention is characterized in that

the solenoid further includes a plunger connected to the rod, a corearranged between the plunger and the valve body, and an electromagneticcoil, and

the second biasing member is disposed between the plunger and the core.

According to this aspect, since the second biasing member is disposedbetween the plunger and the core, it is possible to ensure that thevalve element is biased in the valve opening direction of the main valveportion when the solenoid is turned off.

The capacity control valve according to a sixth aspect of the presentinvention is characterized in that the rod includes a locking portionthat is separated from and comes contact with the valve element.

According to this aspect, the locking portion provided in the rod comesinto contact with the valve element and moves integrally with the valveelement to open and close the main valve portion, and the lockingportion is separated from the valve element, and the rod and the valveelement move relative to each other to press the sensitive element,allowing the auxiliary valve portion to be opened, so that one rod canopen and close different valves.

The capacity control valve according to a seventh aspect of the presentinvention is characterized in that the rod includes a pressing portionthat presses the pressure-sensitive element.

According to this aspect, the pressure-sensitive element is reliablypressed by the pressing portion of the rod to allow the liquidrefrigerant to be efficiently discharged regardless of the pressure inthe suction chamber, so that the compressor can be brought into thecooling operation in a short time.

The capacity control valve according to an eighth aspect of the presentinvention is characterized in that the first pressure is a suctionpressure of the variable capacity compressor, the second pressure is adischarge pressure of the variable capacity compressor, and the thirdpressure is a pressure in a crank chamber of the variable capacitycompressor, or

the first pressure is a pressure in a crank chamber of the variablecapacity compressor, the second pressure is a discharge pressure of thevariable capacity compressor, and the third pressure is a suctionpressure of the variable capacity compressor.

According to this aspect, the present invention can be applied tovarious variable capacity compressors.

In order to solve the above problems, a method of controlling a capacitycontrol valve according to a ninth aspect of the present invention ischaracterized by comprising

when the auxiliary valve portion is in an open state, bringing the mainvalve portion from a closed state into an open state.

According to this aspect, the main valve portion is opened with nobiasing force of the pressure-sensitive element acting on the valveelement during the liquid refrigerant discharge, causing the flow ratefrom the discharge chamber to the control chamber to increase andcausing the load on the compressor to be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front sectional view showing a capacity control valveaccording to a first embodiment of the present invention, and shows acontrol state of the capacity control valve when a third valve chest isunder a low pressure, a solenoid is in an ON state, a main valve isbrought into an open state, and an auxiliary valve is brought into aclosed state.

FIG. 2 is an enlarged view of a valve body, a valve element, and a partof the solenoid, showing the capacity control valve according to thefirst embodiment of the present invention, and shows a liquidrefrigerant discharge state when the third valve chest is under a highpressure, the solenoid is in an ON state, the main valve is brought intoa closed state, and the auxiliary valve is brought into an open state.

FIG. 3 is an enlarged view of the valve body, the valve element, and apart of the solenoid, showing the capacity control valve according tothe first embodiment of the present invention, and shows a state whenthe third valve chest is under a high pressure, the solenoid is in anOFF state, an auxiliary valve portion is kept in an open state, and themain valve is brought into an open state.

FIG. 4 is a front sectional view showing a capacity control valveaccording to a second embodiment of the present invention, and shows acontrol state of the capacity control valve when a third valve chest isunder a low pressure, a solenoid is in an ON state, a main valve isbrought into an open state, and an auxiliary valve is brought into aclosed state.

FIG. 5 is an enlarged view of a valve body, a valve element, and a partof the solenoid, showing the capacity control valve according to thesecond embodiment of the present invention, and shows a liquidrefrigerant discharge state when the third valve chest is under a highpressure, the solenoid is in an ON state, the main valve is brought intoa closed state, and the auxiliary valve is brought into an open state.

FIG. 6 is an enlarged view of the valve body, the valve element, and apart of the solenoid, showing the capacity control valve according tothe second embodiment of the present invention, and shows a state whenthe third valve chest is under a high pressure, the solenoid is in anOFF state, an auxiliary valve portion is kept in an open state, and themain valve is brought into an open state.

FIG. 7 is a front sectional view showing a conventional capacity controlvalve.

FIG. 8 shows the conventional capacity control valve and a state of thecapacity control valve during a liquid refrigerant discharge.

DESCRIPTION OF EMBODIMENTS

Hereinafter with reference to the drawings, a mode for carrying out thepresent invention will be described illustratively based on embodiments.However, the dimensions, materials, shapes, relative positions, andothers of components described in the embodiments are not intended tolimit the present invention only to them unless otherwise explicitlydescribed.

First Embodiment

A capacity control valve according to a first embodiment of the presentinvention will be described with reference to FIGS. 1 to 3 . In FIG. 1 ,reference numeral 1 is a capacity control valve. The capacity controlvalve 1 mainly includes a valve body 10, a valve element 20, apressure-sensitive element 24, and a solenoid 30.

Hereinafter, the respective components constituting the capacity controlvalve 1 will be described with reference to FIG. 1 and FIG. 2 . Thevalve body 10 is composed of a metal such as brass, iron, aluminum,stainless steel, or a synthetic resin material, or the like. The valvebody 10 is a hollow cylindrical member having a through hole thatextends through it in an axial direction with a first valve chest 14, asecond valve chest 15 adjacent to the first valve chest 14, and a thirdvalve chest 16 adjacent to the second valve chest 15 continuouslydisposed in sections of the through hole.

Second communication passages 12 are connected to the second valve chest15. The second communication passages 12 are configured to communicatewith the interior of a discharge chamber (not shown) of the variablecapacity compressor so that the opening and closing of the capacitycontrol valve 1 allows fluid under a discharge pressure Pd (a secondpressure according to the present invention) to flow from the secondvalve chest 15 into the third valve chest 16.

Third communication passages 13 are connected to the third valve chest16. The third communication passages 13 communicate with a controlchamber (not shown) of the variable capacity compressor so that theopening and closing of the capacity control valve 1 causes the fluidunder the discharge pressure Pd flowing from the second valve chest 15into the third valve chest 16 to flow out to the control chamber (thecrank chamber) of the variable capacity compressor, or causes fluidunder a control chamber pressure Pc (a third pressure according to thepresent invention) flowing into the third valve chest 16 to flow out toa suction chamber of the variable capacity compressor through anintermediate communication passage 29 described later and the firstvalve chest 14.

Furthermore, first communication passages 11 are connected to the firstvalve chest 14. The first communication passages 11 guide fluid under asuction pressure Ps (a first pressure according to the presentinvention) from the suction chamber of the variable capacity compressorto the pressure-sensitive element 24 through the intermediatecommunication passage 29 described later so as to control the suctionpressure of the compressor to a set value.

A hole 18 is continuously formed between the first valve chest 14 andthe second valve chest 15, the hole 18 having a diameter smaller thanthese chests. The hole 18 slides in relation to a labyrinth 21 fdescribed later to form a seal portion to seal a gap between the firstvalve chest 14 and the second valve chest 15. In addition, a valve hole17 is continuously provided between the second valve chest 15 and thethird valve chest 16, the valve hole 17 having a diameter smaller thanthese chests. A main valve seat 15 a is formed around the valve hole 17on the side of the second valve chest 15. The main valve seat 15 a isseparated from and comes into contact with a main valve portion 21 cdescribed later to control the opening and closing of the communicationbetween the second valve chest 15 and the third valve chest 16.

The pressure-sensitive element 24 is disposed inside the third valvechest 16. In the pressure-sensitive element 24, one end of a metalbellows 24 a is joined to a partition adjustment portion 24 f in asealed manner. The bellows 24 a is made of phosphor bronze, stainlesssteel or the like, and is designed to have a spring constant of apredetermined value. The interior space of the pressure-sensitiveelement 24 is a vacuum or contains air. Then, the pressure-sensitiveelement 24 is configured such that the pressure acts on an effectivepressure-receiving area of the bellows 24 a of the pressure-sensitiveelement 24 so as to operate to extend and contract thepressure-sensitive element 24. A head portion 24 c is disposed on thefree end side of the pressure-sensitive element 24, and an auxiliaryvalve seat 24 d is formed in the head portion 24 c. The auxiliary valveseat 24 d comes into contact with and is separated from an auxiliaryvalve portion 23 d described later so as to control the opening andclosing of the communication between the third valve chest 16 and theintermediate communication passage 29.

In addition, a flange portion 24 h is formed in the head portion 24 c ofthe pressure-sensitive element 24 and is pressed by a rod 36 of thesolenoid 30 described later. The pressure-sensitive element 24 extendsand contracts by being directly pressed by the rod 36 so that theauxiliary valve portion 23 d is opened and closed. As described later,the pressure-sensitive element 24 extends and contracts according to thesuction pressure Ps guided to the pressure-sensitive element 24 throughthe intermediate communication passage 29, and extends and contracts bythe pressing force of the rod 36.

The partition adjustment portion 24 f of the pressure-sensitive element24 is hermetically fitted and fixed so as to seal off the third valvechest 16 of the valve body 10. If the partition adjustment portion 24 fis screwed and fixed with a set screw (not shown), the spring force ofthe compression spring arranged in parallel within the bellows 24 a orthe bellows 24 a can be axially moved and adjusted.

The first communication passages 11, the second communication passages12, and the third communication passages 13 are, respectively, two tosix in number, for example, and are spaced evenly around a peripheralsurface of the valve body 10, extending therethrough. Furthermore,mounting grooves for O-rings are provided on the outer peripheralsurface of the valve body 10 at three locations spaced apart in theaxial direction. In the respective mounting grooves, O-rings 47, 48, and49 are mounted for sealing a gap between the valve body 10 and amounting hole (not shown) of a casing that is fitted onto the valve body10, and respective flow paths of the first communication passages 11,the second communication passages 12, and the third communicationpassages 13 are configured as independent flow paths.

Next, the valve element 20 will be described. The valve element 20mainly includes a main valve element 21 and an adapter 23 which areformed of a hollow cylindrical member. First, the main valve element 21will be described. The main valve element 21 is a hollow cylindricalmember, and the labyrinth 21 f is formed at a substantially centralportion of the outer peripheral portion in the axial direction of themain valve element 21. The labyrinth 21 f slides in relation to the hole18 formed between the side of the first valve chest 14 and the side ofthe second valve chest 15 to form a seal portion to seal the gap betweenthe first valve chest 14 and the second valve chest 15. Thus, the firstvalve chest 14 and the second valve chest 15 are configured asindependent valve chests.

The main valve element 21 is arranged on the side of the first valvechest 14 and the side of the second valve chest 15 with the labyrinth 21f interposed therebetween. The main valve portion 21 c is formed at anend of the main valve element 21 arranged in the second valve chest 15,and the main valve portion 21 c is separated from and comes into contactwith the main valve seat 15 a to control the opening and closing of thevalve hole 17 that communicates the second valve chest 15 and the thirdvalve chest 16. The main valve portion 21 c and the main valve seat 15 aconstitute a main valve 27. Furthermore, a shutoff valve portion 21 a isformed at an end of the main valve element 21 arranged in the firstvalve chest 14. The shutoff valve portion 21 a comes into contact withan end 32 c of a core 32 to shut off the communication between theintermediate communication passage 29 and the first valve chest 14 whenthe solenoid 30 is turned off as described later. The shutoff valveportion 21 a and the end 32 c of the core 32 constitute a shutoff valve26. The shutoff valve portion 21 a and the main valve portion 21 c ofthe valve element 20 are formed so as to perform opening and closingoperations in opposite directions.

Next, the adapter 23 constituting the valve element 20 will bedescribed. The adapter 23 is a hollow cylindrical member, and mainlyincludes a large diameter portion 23 c formed with a large diameter, anda cylindrical portion 23 e formed with a smaller diameter than the largediameter portion 23 c. The cylindrical portion 23 e is fitted to theopen end of the main valve element 21 on the side of the main valveportion 21 c to constitute the valve element 20. Thus, the intermediatecommunication passage 29 is formed inside the main valve element 21 andthe adapter 23, that is, inside the valve element 20 to extend throughit in the axial direction. In addition, the auxiliary valve portion 23 dis formed in the large diameter portion 23 c of the adapter 23, and theauxiliary valve portion 23 d comes into contact with and is separatedfrom the auxiliary valve seat 24 d formed in the head portion 24 c ofthe pressure-sensitive element 24 to open and close the communicationbetween the third valve chest 16 and the intermediate communicationpassage 29. The auxiliary valve portion 23 d and the auxiliary valveseat 24 d constitute the auxiliary valve 28.

Next, the solenoid 30 will be described. The solenoid 30 includes therod 36, a plunger case 38, an electromagnetic coil 31, a core 32including a center post 32 a and a base member 32 b, a plunger 35, aplate 34, and a solenoid case 33. The plunger case 38 is a bottomedhollow cylindrical member with one end open. The plunger 35 is arrangedso as to be axially movable with respect to the plunger case 38 betweenthe plunger case 38 and the center post 32 a arranged inside the plungercase 38. The core 32 is fitted to the valve body 10 and is arrangedbetween the plunger 35 and the valve body 10. The rod 36 is arranged soas to extend through the center post 32 a of the core 32 and the valveelement 20 arranged in the valve body 10, and there is a gap between theroad 36, and a through hole 32 e of the center post 32 a of the core 32and the intermediate communication passage 29 of the valve element 20,so that the road 36 can move relative to the core 32 and the valveelement 20. Furthermore, one end 36 e of the rod 36 is connected to theplunger 35, and a pressing portion 36 d at the other end is in contactwith the flange portion 24 h of the head portion 24 c of thepressure-sensitive element 24. Thus, the rod 36 can be driven by anelectromagnetic force generated between the core 32 and the plunger 35,and the rod 36 can directly press the pressure-sensitive element 24 toextend and contract the pressure-sensitive element 24. Furthermore, theopen end of the plunger case 38 is fixed to an inner periphery of thebase member 32 b of the core 32 in a sealed manner, and the solenoidcase 33 is fixed to an outer periphery of the base member 32 b in asealed manner. In addition, the electromagnetic coil 31 is arranged in aspace surrounded by the plunger case 38, the base member 32 b of thecore 32, and the solenoid case 33, and does not come into contact withthe refrigerant, allowing a decrease in insulation resistance to beprevented.

Next, a spacer 41 constituting a part of the valve element 20 will bedescribed. The spacer 41 is a cylindrical member having a base 41 e anda flange 41 c extending in the axial direction from the base 41 e, andis fitted and fixed to an inner-diameter portion of the valve element20. The flange 41 c is arranged in contact with a stepped portion 21 bformed between the shutoff valve portion 21 a and the main valve portion21 c at the inner diameter portion of the valve element 20 to form a gapbetween the stepped portion 21 b and the spacer 41. In this gap, aretaining ring 42 (a locking portion according to the present invention)fixed to the rod 36 is arranged. Furthermore, the spacer 41 has a flowhole 41 d through which the refrigerant flows.

The retaining ring 42 fixed to the rod 36 comes into contact with a mainvalve portion side end 41 b of the base 41 e of the spacer 41 fixed tothe valve element 20, so that the driving force of the rod 36 of thesolenoid 30 acts on the valve element 20 as a force in a valve openingdirection of the main valve portion 21 c. On the other hand, theretaining ring 42 fixed to the rod 36 comes into contact with thestepped portion 21 b of the valve element 20, so that the driving forceof the solenoid 30 acts on the valve element 20 as a force in a valveclosing direction of the main valve portion 21 c.

Next, a spring 43 (a first biasing member according to the presentinvention) and a spring 44 (a second biasing member according to thepresent invention) that are disposed with the retaining ring 42interposed therebetween will be described. The spring 43 is disposedbetween the core 32 and the spacer 41 of the valve element 20.Specifically, one end of the spring 43 is in contact with the core 32,and the other end is in contact with a shutoff valve portion side end 41a of the base 41 e of the spacer 41 provided in the valve element 20.Thus, the biasing force of the spring 43 acts on the valve element 20 inthe valve closing direction of the main valve portion 21 c.

Meanwhile, the spring 44 is disposed between the pressure-sensitiveelement 24 and the rod 36. Specifically, one end of the spring 44 is incontact with a stepped portion 36 f formed on the rod 36 between thepressing portion 36 d of the rod 36 and the retaining ring 42, and theother end is in contact with the flange portion 24 h of the head portion24 c of the pressure-sensitive element 24. Thus, the biasing force ofthe spring 44 acts on the valve element 20 through the retaining ring 42and the spacer 41 in the valve opening direction of the main valveportion 21 c. The spring constant of the spring 44 is set to be largerthan the spring constant of the spring 43, and the biasing force of thespring 44 is larger than the biasing force of the spring 43.

The operation of the capacity control valve 1 having the configurationdescribed above will be described. A flow path from the third valvechest 16 to the first valve chest 14 through the intermediatecommunication passage 29 is hereinafter referred to as a “Pc-Ps flowpath”. In addition, a flow path from the second valve chest 15 to thethird valve chest 16 through the valve hole 17 is hereinafter referredto as a “Pd-Pc flow path”.

The operation of each valve, first, when the rod 36 is in a stoppedstate, the rod is in operation, and the rod is then stopped will bedescribed. First, when the solenoid 30 is in a non-energized state, theresultant force of the biasing force of the pressure-sensitive element24 and the biasing force of the spring 44 exceeds the biasing force ofthe spring 43. Therefore, the rod 36 is pushed up to the side of thespring 43, and the retaining ring 42 comes into contact with the spacer41, and the valve element 20 moves in the valve opening direction of themain valve portion 21 c to fully open the main valve portion 21 c, andthe shutoff valve portion 21 a comes into contact with the end 32 c ofthe core 32 to fully close the shutoff valve portion 21 a (see FIG. 3 ).

Next, when the solenoid 30 starts to be energized from the non-energizedstate, the rod 36 is gradually driven in an advancing direction (in thedirection in which the rod 36 projects outward from the end 32 c of thecore 32). At this time, the spacer 41 is pressed downward by the spring43, the retaining ring 42 fixed to the rod 36 and the spacer 41 fixed tothe valve element 20 move in contact with each other, and the rod 36 andthe valve element 20 move integrally. Thus, the shutoff valve portion 21a opens from the fully closed state, and the main valve portion 21 c isgradually narrowed from the fully open state (see FIG. 1 ).

When the rod 36 is further driven in the advancing direction, theshutoff valve portion 21 a is brought into the fully open state, and themain valve portion 21 c comes into contact with the main valve seat 15 ato be brought into the fully closed state, so that the movement of thevalve element 20 is stopped. When the rod 36 is further driven in theadvancing direction from this state, the retaining ring 42 is separatedfrom the spacer 41, the rod 36 moves relative to the main valve element21, and the pressing portion 36 d of the rod 36 presses the flangeportion 24 h of the pressure-sensitive element 24 to contract thesensitive element 24, which allows the auxiliary valve portion 23 d tobe forcibly opened (see FIG. 2 ). When the rod 36 is further driven inthe advancing direction after the auxiliary valve portion 23 d opens,the retaining ring 42 comes into contact with the stepped portion 21 bof the valve element 20, so that the rod 36 is stopped.

Next, a control state of the capacity control valve 1 will be describedwith reference to FIG. 1 . The control state is a state in which theauxiliary valve portion 23 d is in a closed state, and the main valveportion 21 c is set to have a predetermined opening by the solenoid 30so that the pressure in the suction chamber of the variable capacitycompressor is controlled to reach the set value Pset. In this state, thefluid under the suction pressure Ps flowing from the suction chamber ofthe variable capacity compressor to the first valve chest 14 through thefirst communication passages 11 acts on the pressure-sensitive element24 through the intermediate communication passage 29. The main valveportion 21 c is stopped at a position where the force of the spring 43in the valve closing direction, the force of the spring 44 in the valveopening direction, the force of the solenoid 30, and the biasing forceof the pressure-sensitive element 24 that extends and contractsaccording to the suction pressure Ps are balanced. However, the suctionpressure Ps may fluctuate due to disturbance or the like. For example,when the pressure Ps in the suction chamber becomes higher than the setvalue Pset, the pressure-sensitive element 24 contracts and the openingof the main valve portion 21 c becomes smaller. Thus, the Pd-Pc flowpath is narrowed, so that the amount of refrigerant under the dischargepressure Pd flowing from the discharge chamber to the crank chamberreduces and the pressure in the crank chamber decreases. As a result,the angle of inclination of the swash plate of the compressor becomeslarger, and the discharge capacity of the compressor increases, causingthe discharge pressure to decrease. On the other hand, when the pressurePs in the suction chamber becomes lower than the set value Pset, thepressure-sensitive element 24 extends and the opening of the main valveportion 21 c becomes larger. Thus, the Pd-Pc flow path is extended, sothat the amount of refrigerant under the discharge pressure Pd flowingfrom the discharge chamber to the crank chamber increases, and thepressure in the crank chamber increases. As a result, the angle ofinclination of the swash plate of the compressor becomes smaller,causing the discharge capacity of the compressor to reduce and causingthe discharge pressure to increase. Thus, the capacity control valve 1can control the pressure in the suction chamber of the variable capacitycompressor so as to reach the set value Pset.

Next, a liquid refrigerant discharge state of the capacity control valve1 will be described with reference to FIG. 2 . After the compressor isstopped for a long period of time, a liquid refrigerant (a refrigerantthat has been liquefied by cooling while the compressor is inoperative)is accumulated in the crank chamber. Therefore, in order to secure apredetermined discharge pressure and discharge flow rate afteractivating the compressor, it is necessary to discharge the liquidrefrigerant as quickly as possible. During the liquid refrigerantdischarge, the pressure in the third valve chest 16 communicating withthe crank chamber becomes higher and the suction pressure Ps alsobecomes higher. Thus, the pressure-sensitive element 24 contracts andthe valve element 20 is pressed downward by the spring 43, so that themain valve portion 21 c is brought into a closed state and the auxiliaryvalve portion 23 d is brought into an open state. Even in this state,the liquid refrigerant can be discharged from the crank chamber to thesuction chamber through the Pc-Ps flow path. However, as the dischargeof the liquid refrigerant discharge progresses, the pressure in thethird valve chest 16 and the suction pressure Ps gradually decrease, sothat the opening of the auxiliary valve portion 23 d gradually becomessmaller, resulting in an increase in time to complete the discharge ofthe liquid refrigerant. Then, the solenoid 30 is driven in the advancingdirection, and the pressure-sensitive element 24 is pressed by the rod36 to forcibly bring the auxiliary valve portion 23 d into the fullyopen state. Thus, the auxiliary valve portion 23 d is kept in the fullyopen state, so that the opening of the auxiliary valve portion 23 d doesnot change from the start of the liquid refrigerant discharge to thecompletion of the liquid refrigerant discharge, allowing the liquidrefrigerant to be discharged from the crank chamber to the suctionchamber thorough the Pc-Ps flow path in a short time.

In addition, conventionally, during the liquid refrigerant dischargeoperation, attention has been focused only on how to complete thedischarge of the liquid refrigerant in a short time regardless of theengine load. However, even during the liquid refrigerant discharge, whenthe engine output is high, the load on the load compressor may bedesired to be reduced. In addition, during the liquid refrigerantdischarge, the auxiliary valve portion 23 d is brought into the openstate, so that no biasing force acts on the valve element 20 from thepressure-sensitive element 24, making it difficult to quickly drive thevalve element 20. The capacity control valve 1 according to the presentinvention can easily drive the valve element 20 even during the liquidrefrigerant discharge.

Hereinafter, the operation of the capacity control valve 1 for reducingthe engine load during the liquid refrigerant discharge will bedescribed with reference to FIG. 3 . In order to reduce the engine loadduring the liquid refrigerant discharge, the solenoid 30 is turned off,and a magnetic attractive force Fsol between the core 32 and the plunger35 is set to zero. At this time, since the upward pressure and thedownward pressure acting on the valve element 20 are set to be balanced,the main force acting on the valve element 20 is the biasing force ofthe spring 44 and the spring 43. Since the biasing force of the spring44 is set to be larger than the biasing force of the spring 43, the rod36 is pushed up by the biasing force of the spring 44, the retainingring 42 comes into contact with the spacer 41 so that the valve element20 is driven, and the main valve portion 21 c is fully opened. When themain valve portion 21 c is fully opened, the amount of refrigerantflowing from the discharge chamber of the compressor to the crankchamber through the Pd-Pc flow path increases and the pressure Pc in thecrank chamber becomes higher, so that the compressor is operated withthe minimum capacity. Thus, likewise during the liquid refrigerantdischarge, even when the auxiliary valve portion 23 d is in the openstate and no force acts on the valve element 20 from thepressure-sensitive element 24, bringing the main valve portion 21 c intothe fully open state from the fully closed state enables the load on thecompressor to be reduced, and thus enables the engine load to be reducedalso during the liquid refrigerant discharge.

Furthermore, also in order to reduce the load on the engine in anoperation state in which the capacity control valve 1 controls thepressure in the suction chamber of the compressor so as to reach the setvalue Pset, as described above, by bringing the solenoid 30 into thenon-energized state, the main valve portion 21 c is brought into thefully open state to allow the load on the engine to be reduced.

Thus, the rod 36 moves integrally with the valve element 20 while themain valve portion 21 c is brought from the fully open state into thefully closed state, and after the main valve portion 21 c is fullyclosed, the rod 36 moves relative to the valve element 20 to press thesensitive element 24, allowing the auxiliary valve portion 23 d to beopened. That is, one rod 36 can open and close the main valve portion 21c and the auxiliary valve portion 23 d, which are different. Inaddition, since the spring constant of the spring 44 is set to be largerthan the spring constant of the spring 43, and the biasing force of thespring 44 is larger than the biasing force of the spring 43, the openingand closing states of the main valve portion 21 c and the auxiliaryvalve portion 23 d can be opened and closed in any combination. That is,the main valve portion 21 c can be opened while the auxiliary valveportion 23 d be opened, the main valve portion 21 c can be opened whilethe auxiliary valve portion 23 d be closed, the main valve portion 21 ccan be closed while the auxiliary valve portion 23 d be opened, and themain valve portion 21 c can be closed while the auxiliary valve portion23 d be closed.

Second Embodiment

A capacity control valve according to a second embodiment of the presentinvention will be described with reference to FIGS. 4 to 6 . In FIG. 4 ,reference numeral 100 is a capacity control valve. The capacity controlvalve 100 mainly includes a valve body 110, a valve element 120, apressure-sensitive element 124, and a solenoid 130.

The respective components constituting the capacity control valve 100will be described with reference to FIG. 4 and FIG. 5 . The capacitycontrol valve 100 mainly includes the valve body 110, the valve element120, the pressure-sensitive element 124, and the solenoid 130.

The valve body 110 is composed of a metal such as brass, iron, aluminum,stainless steel, or a synthetic resin material, or the like. The valvebody 110 is a hollow cylindrical member having a through hole thatextends through it in an axial direction with a first valve chest 114, asecond valve chest 115 adjacent to the first valve chest 114, and athird valve chest 116 adjacent to the second valve chest 115continuously disposed in sections of the through hole.

Second communication passage 112 are connected to the second valve chest115. The second communication passages 112 are configured to communicatewith the inside of a discharge chamber (not shown) of the variablecapacity compressor so that the opening and closing of the capacitycontrol valve 100 allows fluid under the discharge pressure Pd to flowfrom the second valve chest 115 into the third valve chest 116.

Third communication passage 113 are connected to the third valve chest116. The third communication passages 113 communicate with a controlchamber (not shown) of the variable capacity compressor so that theopening and closing of the capacity control valve 100 causes the fluidunder the discharge pressure Pd flowing from the second valve chest 115into the third valve chest 116 to flow out to the control chamber (thecrank chamber) of the variable capacity compressor, or causes fluidunder the control chamber pressure Pc flowing into the third valve chest116 to flow out to a suction chamber of the variable capacity compressorthrough an intermediate communication passage 129 described later andthe first valve chest 114.

Furthermore, first communication passages 111 are connected to the firstvalve chest 114. The first communication passages 111 guide fluid underthe suction pressure Ps from the suction chamber of the variablecapacity compressor to the pressure-sensitive element 124 through theintermediate communication passage 129 described later to control thesuction pressure of the compressor to a set value.

A hole 118 is continuously formed between the first valve chest 114 andthe second valve chest 115, the hole 118 having a diameter smaller thanthese chests. The hole 118 slides in relation to a labyrinth 121 fdescribed later to form a seal portion to seal a gap between the firstvalve chest 114 and the second valve chest 115. In addition, a valvehole 117 is continuously provided between the second valve chest 115 andthe third valve chest 116, the valve hole 117 having a diameter smallerthan these chests. A main valve seat 115 a is formed around the valvehole 117 on the side of the second valve chest 115. The main valve seat115 a is separated from and comes into contact with a main valve portion121 c described later to control the opening and closing of thecommunication between the second valve chest 115 and the third valvechest 116.

The pressure-sensitive element 124 is disposed inside the third valvechest 116. In the pressure-sensitive element 124, one end of a metalbellows 124 a is joined to a partition adjustment portion 124 f in asealed manner. The bellows 124 a is made of phosphor bronze, stainlesssteel or the like, and is designed to have a spring constant of apredetermined value. The interior space of the pressure-sensitiveelement 124 is a vacuum or contains air. Then, the pressure-sensitiveelement 124 is configured such that the pressure acts on an effectivepressure-receiving area of the bellows 124 a of the pressure-sensitiveelement 124 so as to operate to extend and contract thepressure-sensitive element 124. A head portion 124 c is disposed on thefree end side of the pressure-sensitive element 124, and an auxiliaryvalve seat 124 d is formed in the head portion 124 c. The auxiliaryvalve seat 124 d comes into contact with and is separated from anauxiliary valve portion 123 d described later to control the opening andclosing of the communication between the third valve chest 116 and theintermediate communication passage 129.

In addition, the head portion 124 c of the pressure-sensitive element124 extends and contracts by being pressed by a rod 136 of the solenoid130 described later so that the auxiliary valve portion 123 d is openedand closed. As described later, the pressure-sensitive element 124extends and contracts according to the suction pressure Ps guided to thepressure-sensitive element 124 through the intermediate communicationpassage 129, and extends and contracts by the pressing force of the rod136.

The partition adjustment portion 124 f of the pressure-sensitive element124 is hermetically fitted and fixed so as to seal off the third valvechest 116 of the valve body 110. If the partition adjustment portion 124f is screwed and fixed with a set screw (not shown), the spring force ofthe compression spring arranged in parallel within the bellows 124 a orthe bellows 124 a can be axially moved and adjusted.

The first communication passages 111, the second communication passages112, and the third communication passages 113 are, respectively, two tosix in number, for example, and are spaced evenly around a peripheralsurface of the valve body 110, extending therethrough. Furthermore,mounting grooves for O-rings are provided on the outer peripheralsurface of the valve body 110 at three locations spaced apart in theaxial direction. In the respective mounting grooves, O-rings 147, 148,and 149 are mounted for sealing a gap between the valve body 110 and amounting hole (not shown) of a casing that is fitted onto the valve body110. Respective flow paths of the first communication passages 111, thesecond communication passages 112, and the third communication passages113 are configured as independent flow paths.

Next, the valve element 120 will be described. The valve element 120mainly includes a main valve element 121 and an adapter 123, which areformed of a hollow cylindrical member. First, the main valve element 121will be described. The main valve element 121 is a hollow cylindricalmember, and the labyrinth 121 f is formed at a substantially centralportion of the outer peripheral portion in the axial direction of themain valve element 121. The labyrinth 121 f slides in relation to thehole 118 formed between the side of the first valve chest 114 and theside of the second valve chest 115 to form a seal portion to seal thegap between the first valve chest 114 and the second valve chest 115.Thus, the first valve chest 114 and the second valve chest 115 areconfigured as independent valve chests.

The main valve element 121 is arranged on the side of the first valvechest 114 and the side of the second valve chest 115 with the labyrinth121 f interposed therebetween. The main valve portion 121 c is formed atan end of the main valve element 121 arranged in the second valve chest115, and the main valve portion 121 c is separated from and comes intocontact with the main valve seat 115 a to control the opening andclosing of the valve hole 117 that communicates the second valve chest115 and the third valve chest 116. The main valve portion 121 c and themain valve seat 115 a constitute a main valve 127. Furthermore, ashutoff valve portion 121 a is formed at an end of the main valveelement 121 arranged in the first valve chest 114. The shutoff valveportion 121 a comes into contact with an end 132 c of a core 132 whenthe solenoid 130 is turned off as described later to shut off thecommunication between the intermediate communication passage 129 and thefirst valve chest 114. The shutoff valve portion 1 121 a and the end 132c of the core 132 constitute a shutoff valve 126. The shutoff valveportion 121 a and the main valve portion 121 c are formed so as toperform opening and closing operations in opposite directions.

Next, the adapter 123 constituting the valve element 120 will bedescribed. The adapter 123 is a hollow cylindrical member and mainlyincludes a large diameter portion 123 c formed with a large diameter,and a cylindrical portion 123 e formed with a smaller diameter than thelarge diameter portion 123 c. The cylindrical portion 123 e is fitted tothe open end of the main valve element 121 on the side of the main valveportion 121 c to constitute the valve element 120. Thus, theintermediate communication passage 129 is formed inside the main valveelement 121 and the adapter 123, that is, inside the valve element 120to extend through it in the axial direction. In addition, the auxiliaryvalve portion 123 d is formed at the distal end of the large diameterportion 123 c, and the auxiliary valve portion 123 d comes into contactwith and is separated from the auxiliary valve seat 124 d of thepressure-sensitive element 124 to open and close the communicationbetween the third valve chest 116 and the intermediate communicationpassage 129. The auxiliary valve portion 123 d and the auxiliary valveseat 124 d constitute the auxiliary valve 128.

Next, the solenoid 130 will be described. The solenoid 130 includes therod 136, a plunger case 138, an electromagnetic coil 131, a core 132including a center post 132 a and a base member 132 b, a plunger 135, aplate 134, and a solenoid case 133. The plunger case 138 is a bottomedhollow cylindrical member with one end open. The plunger 135 is arrangedso as to be axially movable with respect to the plunger case 138 betweenthe plunger case 138 and a center post 132 a arranged inside the plungercase 138. The core 132 is fitted to the valve body 110 and is arrangedbetween the plunger 135 and the valve body 110. The rod 136 is arrangedso as to extend through the center post 132 a of the core 132 and thevalve element 120 arranged in the valve body 110, and there is a gapbetween the road 136, and a through hole 132 e of the center post 132 aof the core 132 and the intermediate communication passage 129 of thevalve element 120, so that the road 136 can move relative to the core132 and the valve element 120. Furthermore, one end 136 e of the rod 136is connected to the plunger 135, and a pressing portion 136 d at theother end is in contact with the head portion 124 c of thepressure-sensitive element 124. Thus, the rod 136 can be driven by anelectromagnetic force generated between the core 132 and the plunger135, and the rod 136 can directly press the pressure-sensitive element124 to extend and contract the pressure-sensitive element 124.

A spring 137 (a second biasing member according to the presentinvention) is arranged between the core 132 and the plunger 135 forbiasing the plunger 135 so that the plunger 135 is separated from thecore 132. Thus, the biasing force of the spring 137 acts in a directionto open the main valve portion 121 c of the valve element 120.

Furthermore, the open end of the plunger case 138 is fixed to an innerperiphery of the base member 132 b of the core 132 in a sealed manner,and the solenoid case 133 is fixed to an outer periphery of the basemember 132 b in a sealed manner. In addition, the electromagnetic coil131 is arranged in a space surrounded by the plunger case 138, the basemember 132 b of the core 132, and the solenoid case 133, and does notcome into contact with the refrigerant, allowing a decrease ininsulation resistance to be prevented.

Next, a retaining ring 142 (a locking portion according to the presentinvention) constituting a part of the rod 136 will be described. In theretaining ring 142, a communication passage is formed so as not toprevent the communication between the third valve chest 116 and theintermediate communication passage 129. The retaining ring 142 is adisk-shaped member, and is fitted and fixed to the rod 136 so as to belocated between the adapter 123 and the head portion 124 c of thepressure-sensitive element 124. The retaining ring 142 comes intocontact with the adapter 123 of the valve element 120, so that thedriving force of the rod 136 of the solenoid 130 acts on the valveelement 120 as a force in the valve opening direction of the main valveportion 121 c. On the other hand, the retaining ring 142 fixed to therod 136 comes into contact with the head portion 124 c of thepressure-sensitive element 124, so that the driving force of the rod 136of the solenoid 130 directly presses the pressure-sensitive element 124to extend and contract the pressure-sensitive element 124.

Here, a protrusion 124 h is formed at the central portion of the headportion 124 c of the pressure-sensitive element 124, and a protrusion(not shown) is formed also at the central portion of the partitionadjustment portion 124 f of the pressure-sensitive element 124 facingthe auxiliary valve seat 124 d. When the retaining ring 142 fixed to therod 136 comes into contact with the head portion 124 c of thepressure-sensitive element 124, the pressure-sensitive element 124 iscontracted. When the pressure-sensitive element 124 is contracted by apredetermined amount, the protrusion 124 h and the protrusion of thepartition adjustment portion 124 f come into contact with each other sothat the deformation of the pressure-sensitive element 124 is restrictedand the movement of the rod 136 is also restricted.

Next, a spring 143 (a first biasing member according to the presentinvention) will be described. The spring 143 is disposed between thesolenoid 130 and the valve element 120. Specifically, one end of thespring 143 is in contact with the core 132, and the other end is incontact with a stepped portion 121 b formed between the shutoff valveportion 121 a and the labyrinth 121 f of the valve element 120. Thus,the biasing force of the spring 143 acts in a direction to close themain valve portion 121 c of the valve element 120.

The spring constant of the spring 137 (the second biasing member)provided between the core 132 and the plunger 135 is set larger than thespring constant of the spring 143 (the first biasing member), and thebiasing force of the spring 137 is larger than the biasing force of thespring 143.

The operation of the movement of the rod 136 and the movement of eachvalve portion of the capacity control valve 100 having the configurationdescribed above will be described. A flow path from the third valvechest 116 to the first valve chest 114 through the intermediatecommunication passage 129 is hereinafter referred to as “Pc-Ps flowpath”. A flow path from the second valve chest 115 to the third valvechest 116 through the valve hole 117 is hereinafter referred to as“Pd-Pc flow path”.

The operation of each valve, first, when the rod 136 is in a stoppedstate, the rod 136 is in operation, and the rod 136 is then stopped willbe described with reference to FIG. 6 . First, when the solenoid 130 isin a non-energized state, the resultant force of the biasing force ofthe pressure-sensitive element 124 and the biasing force of the spring137 (FIG. 4 ) exceeds the biasing force of the spring 143. Therefore,the rod 136 is pushed upward, and the retaining ring 142 comes intocontact with the adapter 123, so that the adapter 123 is pressed tofully open the main valve portion 121 c, and the shutoff valve portion121 a comes into contact with the end 132 c of the core 132 to fullyclose the shutoff valve portion 121 a.

Next, when the solenoid 130 starts to be energized from thenon-energized state, the rod 136 is gradually driven in an advancingdirection (in the direction in which the rod 136 projects outward fromthe end 132 c of the core 132). At this time, the valve element 120 ispressed downward by the spring 143, the retaining ring 142 fixed to therod 136 and the adapter 123 of the valve element 120 move in contactwith each other, and the rod 136 and the valve element 120 also moveintegrally. Thus, the shutoff valve portion 121 a opens from the fullyclosed state, and the opening of the main valve portion 121 c isgradually narrowed (see FIG. 4 ).

When the rod 136 is further driven in the advancing direction, as shownin FIG. 5 , the shutoff valve portion 121 a is brought into the fullyopen state, and the main valve portion 121 c comes into contact with themain valve seat 115 a to be brought into the fully closed state, so thatthe movement of the main valve element 121 is stopped. When the rod 136is further driven in the advancing direction from this state, the rod136 moves relative to the main valve element 121, and the retaining ring142 is separated from the adapter 123. When the rod 136 is furtherdriven, the retaining ring 142 of the rod 136 comes into contact withthe head portion 124 c of the pressure-sensitive element 124, andpresses the head portion 124 c to contract the pressure-sensitiveelement 124, which allows the auxiliary valve portion 123 d to beforcibly opened. When the pressure-sensitive element 124 is contractedby a predetermined amount, the protrusion 124 h and the protrusion (notshown) of the partition adjustment portion 124 f come into contact witheach other so that the deformation of the pressure-sensitive element 124is restricted and the movement of the rod 136 is also stopped (see FIG.5 ). In addition, instead of pressing the head portion 124 c of thepressure-sensitive element 124 by the retaining ring 142 to contract thepressure-sensitive element 124, the pressing portion 136 d of the rod136 may press the head portion 124 c of the pressure-sensitive element124 to contract the pressure-sensitive element 124, causing theauxiliary valve portion 123 d to be forcibly opened.

Next, a control state of the capacity control valve 100 will bedescribed with reference to FIG. 4 . The control state is a state inwhich the auxiliary valve portion 123 d is in a closed state, and themain valve portion 121 c is set to have a predetermined opening by thesolenoid 130 so that the pressure in the suction chamber of the variablecapacity compressor is controlled to reach the set value Pset. In thisstate, the fluid under the suction pressure Ps flowing from the suctionchamber of the variable capacity compressor to the first valve chest 114through the first communication passages 111 acts on thepressure-sensitive element 124 through the intermediate communicationpassage 129. As a result, the main valve portion 121 c is stopped at aposition where the force of the spring 143 in the valve closingdirection, the force of the spring 137 in the valve opening direction,the force of the solenoid 130, and the force of the pressure-sensitiveelement 124 that extends and contracts according to the suction pressurePs are balanced. However, the pressure Ps in the suction chamber maybecome higher than the set value Pset due to disturbance or the like.For example, when the pressure Ps in the suction chamber becomes higherthan the set value Pset due to disturbance or the like, thepressure-sensitive element 124 contracts and the opening of the mainvalve portion 121 c becomes smaller. Thus, the Pd-Pc flow path isnarrowed, so that the amount of refrigerant under the discharge pressurePd flowing from the discharge chamber to the crank chamber reduces andthe pressure in the crank chamber decreases. As a result, the angle ofinclination of the swash plate of the compressor becomes larger, and thedischarge capacity of the compressor increases, causing the dischargepressure to decrease. On the other hand, when the pressure Ps in thesuction chamber becomes lower than the set value Pset, thepressure-sensitive element 124 extends and the opening of the main valveportion 121 c becomes larger. Thus, the Pd-Pc flow path is extended, sothat the amount of refrigerant under the discharge pressure Pd flowingfrom the discharge chamber to the crank chamber increases, and thepressure in the crank chamber increases. As a result, the angle ofinclination of the swash plate of the compressor becomes smaller,causing the discharge capacity of the compressor to reduce and causingthe discharge pressure to increase. Thus, the capacity control valve 100can control the pressure in the suction chamber of the variable capacitycompressor so as to reach the set value Pset.

Next, when a liquid refrigerant (a refrigerant that has been liquefiedby cooling while the compressor is inoperative) is accumulated in thecrank chamber after the compressor is stopped for a long period of time,the operation of the capacity control valve 100 for discharging theliquid refrigerant will be described based on FIG. 5 . During the liquidrefrigerant discharge, the pressure in the third valve chest 116communicating with the crank chamber becomes higher and the suctionpressure Ps also becomes higher. Therefore, the pressure-sensitiveelement 124 contracts under the high-pressure suction pressure Ps sothat the auxiliary valve portion 123 d is brought into an open state.When the solenoid 130 is driven in the advancing direction, the mainvalve portion 121 c is brought into the fully closed state, and theretaining ring 142 of the rod 136 presses the pressure-sensitive element124 to forcibly open the auxiliary valve portion 123 d, so that theauxiliary valve portion 123 d is brought into the fully open state. Thepressure-sensitive element 124 is pressed by the rod 136 so that theauxiliary valve portion 123 d is kept in the fully open state.Therefore, the opening of the auxiliary valve portion 123 d does notchange from the start of the liquid refrigerant discharge to thecompletion of the liquid refrigerant discharge and can be kept in thefully open state, allowing the liquid refrigerant to be discharge fromthe crank chamber to the suction chamber thorough the Pc-Ps flow path ina short time. On the other hand, when the pressure-sensitive element 124is not pressed by the rod 136 of the solenoid 130 to forcibly open theauxiliary valve portion 123 d, as the discharge of the liquidrefrigerant discharge progresses, the pressure in the third valve chest116 and the suction pressure Ps decrease, so that the opening of theauxiliary valve portion 123 d gradually becomes smaller, resulting in anincrease in time to complete the discharge of the liquid refrigerant.Therefore, the preset discharge amount cannot be secured in a shorttime.

In addition, conventionally, during the liquid refrigerant dischargeoperation, attention has been focused only on how to complete thedischarge of the liquid refrigerant in a short time, and the control forreducing the engine load in process of the liquid refrigerant dischargeoperation was not performed. Meanwhile, during the liquid refrigerantdischarge, the auxiliary valve portion 123 d is brought into the openstate, so that no biasing force acts on the valve element 120 from thepressure-sensitive element 124, causing it difficult to quickly drivethe valve element 120. The capacity control valve 100 according to thepresent invention enables can easily drive the valve element 120 evenduring the liquid refrigerant discharge.

The operation of the capacity control valve 100 for reducing the engineload during the liquid refrigerant discharge will be described withreference to FIG. 6 . In order to reduce the engine load during theliquid refrigerant discharge, the solenoid 130 is turned off, and amagnetic attractive force Fsol between the core 132 and the plunger 135is set to zero. At this time, since the upward pressure and the downwardpressure acting on the valve element 120 are set to be balanced, themain force acting on the valve element 120 is the biasing force of thespring 137 and the spring 143. Additionally, the biasing force of thespring 137 is set to be larger than the biasing force of the spring 143.Therefore, the rod 136 is pushed up by the biasing force of the spring137, the retaining ring 142 comes into contact with the adapter 123 sothat the valve element 120 is driven, and the main valve portion 121 cis fully opened. When the main valve portion 121 c is fully opened, theamount of refrigerant flowing from the discharge chamber of thecompressor to the crank chamber through the Pd-Pc flow path increasesand the pressure Pc in the crank chamber increases, so that thecompressor is operated with the minimum capacity. Thus, likewise duringthe liquid refrigerant discharge, even when the auxiliary valve portion123 d is in the open state and no force acts on the valve element 120from the pressure-sensitive element 124, bringing the main valve portion121 c from the fully closed state into the fully open state enables theload on the compressor to be reduced, and thus enables the engine loadto be reduced also during the liquid refrigerant discharge.

Furthermore, also in order to reduce the load on the engine in thecontrol state in which the capacity control valve 100 controls thepressure in the suction chamber of the compressor so as to reach the setvalue Pset, as described above, by bringing the solenoid 130 into thenon-energized state, the main valve portion 121 c is brought into thefully open state to increase the amount of refrigerant under thepressure Pd flowing from the discharge chamber of the compressor to thecrank chamber through the Pd-Pc flow path, allowing the compressor tooperate with a minimum capacity and perform the operation for reducingthe load on the engine.

Thus, the rod 136 moves integrally with the valve element 120 while themain valve portion 121 c is brought from the fully open state into thefully closed state, and after the main valve portion 121 c is fullyclosed, the rod 136 moves relative to the valve element 120 to press thesensitive element 124, allowing the auxiliary valve portion 123 d to beopened. That is, one rod 136 can open and close the main valve portion121 c and the auxiliary valve portion 123 d, which are different. Inaddition, since the spring constant of the spring 137 is set to belarger than the spring constant of the spring 143, and the biasing forceof the spring 137 is larger than the biasing force of the spring 143,the opening and closing states of the main valve portion 121 c and theauxiliary valve portion 123 d can be opened and closed in any state.That is, the main valve portion 121 c can be opened while the auxiliaryvalve portion 123 d be opened, the main valve portion 121 c can beopened while the auxiliary valve portion 123 d be closed, while the mainvalve portion 121 c can be closed the auxiliary valve portion 123 d beopened, while the main valve portion 121 c can be closed and theauxiliary valve portion 123 d be closed.

Although the embodiments according to the present invention have beendescribed using the drawings, their specific configuration is notlimited to these embodiments. Any changes and additions made withoutdeparting from the scope of the present invention are included in thepresent invention.

For example, in the second embodiment, the spring 143 is arranged on theouter peripheral side of the main valve element 121 in the first valvechest 114, but is not limited thereto. For example, it may be arrangedon the inner peripheral side of the main valve element 121 in the firstvalve chest 114 so that its one end is in contact with the core 132 andthe other end is in contact with the valve element 120.

Furthermore, in the above embodiments, a first pressure in the firstvalve chest 14 (114) is the suction pressure Ps of the variable capacitycompressor, a second pressure in the second valve chest 15 (115) is thedischarge pressure Pd of the variable capacity compressor, and a thirdpressure in the third valve chest 16 (116) is the pressure Pc in thecrank chamber of the variable capacity compressor, but is not limited tothis. The first pressure in the first valve chest 14 (114) may be thepressure Pc in the crank chamber of the variable capacity compressor,the second pressure in the second valve chest 15 (115) be the dischargepressure Pd of the variable capacity compressor, and the third pressurein the third valve chest 16 (116) be the suction pressure Ps of thevariable capacity compressor, so that the present invention can beapplied to various variable capacity compressors.

REFERENCE SIGNS LIST

-   -   1 capacity control valve    -   10 valve body    -   11 first communication passage    -   12 second communication passage    -   13 third communication passage    -   14 first valve chest    -   15 second valve chest    -   15 a main valve seat    -   16 third valve chest    -   17 valve hole    -   20 valve element    -   21 main valve element    -   21 a shutoff valve portion    -   21 c main valve portion    -   23 adapter    -   23 d auxiliary valve portion    -   24 pressure-sensitive element    -   24 a bellows    -   24 d auxiliary valve seat    -   27 main valve    -   28 auxiliary valve    -   29 intermediate communication passage 30 solenoid unit    -   31 electromagnetic coil    -   32 core    -   33 solenoid case    -   35 plunger    -   36 rod    -   38 plunger case    -   41 spacer    -   42 retaining ring (locking portion)    -   43 spring (first biasing member)    -   44 spring (second biasing member)    -   100 capacity control valve    -   110 valve body    -   111 first communication passage    -   112 second communication passage    -   113 third communication passage    -   114 first valve chest    -   115 second valve chest    -   115 a main valve seat    -   116 third valve chest    -   117 valve hole    -   120 valve element    -   121 main valve element    -   121 a shutoff valve portion    -   121 c main valve portion    -   123 adapter    -   123 d auxiliary valve portion    -   124 pressure-sensitive element    -   124 a bellows    -   124 d auxiliary valve seat    -   127 main valve    -   128 auxiliary valve    -   129 intermediate communication passage    -   130 solenoid    -   131 electromagnetic coil    -   132 core    -   133 solenoid case    -   135 plunger    -   136 rod    -   137 spring (second biasing member)    -   138 plunger case    -   142 retaining ring (locking member)    -   143 spring (first biasing member)    -   Fsol magnetic attractive force    -   Ps suction pressure (first pressure) (third pressure)    -   Pd discharge pressure    -   Pc control chamber pressure (third pressure) (first pressure)    -   Pset suction pressure set value

1. A capacity control valve that controls a flow rate or a pressure of avariable capacity compressor according to a valve opening of a valveunit, characterized by comprising: a valve body including firstcommunication passages that pass fluid under a first pressure, secondcommunication passages that are arranged adjacent to the firstcommunication passages and pass fluid under a second pressure, thirdcommunication passages that pass fluid under a third pressure, and amain valve seat that is disposed in a valve hole communicating thesecond communication passages and the third communication passages; apressure-sensitive element that is arranged in the valve body on theside of the third communication passages and extends and contracts inresponse to an ambient pressure; a valve element including anintermediate communication passage that communicates the firstcommunication passages and the third communication passages, a mainvalve portion that is separated from and comes into contact with themain valve seat to open and close the valve hole, and an auxiliary valveportion that is separated from and comes into contact with thepressure-sensitive element to open and close the intermediatecommunication passage; a solenoid that drives a rod; a first biasingmember that biases in a valve closing direction of the main valveportion; and a second biasing member that biases in a valve openingdirection of the main valve portion, wherein the rod moves relative tothe valve element to press the pressure-sensitive element, wherein thesolenoid further includes a plunger connected to the rod, a corearranged between the plunger and the valve body, and an electromagneticcoil, and the second biasing member is disposed between the plunger andthe core.
 2. The capacity control valve according to claim 1, wherein abiasing force of the second biasing member is larger than a biasingforce of the first biasing member.
 3. The capacity control valveaccording to claim 1, wherein the first biasing member is disposedbetween the solenoid and the valve element.
 4. The capacity controlvalve according to claim 1, wherein the rod includes a locking portionthat is separated from and comes contact with the valve element.
 5. Thecapacity control valve according to claim 1, wherein the rod includes apressing portion that presses the pressure-sensitive element.
 6. Thecapacity control valve according to claim 1, wherein the first pressureis a suction pressure of the variable capacity compressor, the secondpressure is a discharge pressure of the variable capacity compressor,and the third pressure is a pressure in a crank chamber of the variablecapacity compressor.
 7. The capacity control valve according to claim 1,wherein the first pressure is a pressure in a crank chamber of thevariable capacity compressor, the second pressure is a dischargepressure of the variable capacity compressor, and the third pressure isa suction pressure of the variable capacity compressor.
 8. A method ofcontrolling a capacity control valve, characterized by comprising usingthe capacity control valve according to claim 1, when the auxiliaryvalve portion is in an open state, bringing the main valve portion froma closed state into an open state.
 9. The capacity control valveaccording to claim 2, wherein the first biasing member is disposedbetween the solenoid and the valve element.
 10. The capacity controlvalve according to claim 2, wherein the rod includes a locking portionthat is separated from and comes contact with the valve element.
 11. Thecapacity control valve according to claim 2, wherein the rod includes apressing portion that presses the pressure-sensitive element.
 12. Thecapacity control valve according to claim 2, wherein the first pressureis a suction pressure of the variable capacity compressor, the secondpressure is a discharge pressure of the variable capacity compressor,and the third pressure is a pressure in a crank chamber of the variablecapacity compressor.
 13. The capacity control valve according to claim2, wherein the first pressure is a pressure in a crank chamber of thevariable capacity compressor, the second pressure is a dischargepressure of the variable capacity compressor, and the third pressure isa suction pressure of the variable capacity compressor.
 14. A method ofcontrolling a capacity control valve comprising using the capacitycontrol valve according to claim 2, when the auxiliary valve portion isin an open state, bringing the main valve portion from a closed stateinto an open state.